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COMMERCIAL hatcherymen have observed that fertile eggs from pullets just starting to lay do not hatch well and that mortality rate in the chicks which do hatch is abnormally high. Sunde and Bird (1959) observed that both fertility and hatchability of fertile eggs was much lower in eggs from pullets just starting to lay than it was in eggs laid six weeks later. Much of the embryonic mortality in the first laid eggs occurred during the first week of incubation. Such dietary factors as vitamin levels, protein levels, antibiotic levels and vegetable vs. animal protein were found to have no effect on improving the hatchability of eggs from young breeder hens. This paper will present evidence that level of calcium in the laying diet may affect hatchability of eggs and growth and viability of chicks from pullets just starting to lay. EXPERIMENTAL The data to be presented were secured as …

IN PREVIOUS studies at this station, Berg et al. (1962), it was observed that the incidence of an abnormal wing feather condition increased among chicks hatched from eggs laid by breeder pullets just entering production, as level of calcium in the maternal diet was increased. The abnormal wing feather condition, which was similar to that described by Young et al. (1958) as a symptom of zinc deficiency, was markedly decreased in chicks hatched from eggs laid four weeks after the pullets had reached 30 percent lay. Symptoms of zinc deficiency in the chicks were evident even though the chick diet calculated to contain 38 p.p.m. 2 of zinc and the chicks were kept in galvanized metal batteries. This paper will present further evidence as to the effect of calcium level of the breeder diet on abnormal wing feather development of chicks, and evidence for an abnormally high zinc requirement at the…

THE National Research Council (1960) has set the calcium and phosphorus requirements of growing chickens from 8 to 18 weeks of age at 1.0 and 0.6%, respectively. It is further indicated that a portion of the phosphorus must be supplied in inorganic form. Evidence to support such high requirements for these two elements during the developing period (8 weeks to 18 to 21 weeks of age) is meager. Numerous investigations have indicated that the above indicated values are necessary for early chick growth and normal bone ash. However, few studies have been conducted to determine requirements during the growing or developing period. Berg el al. (1947) found no difference in the performance of laying pullets fed diets containing 0.7, 0.9 or 3.0% calcium for an average of eight weeks prior to the onset of lay. O’Rourke et al. (1952) showed that the phosphorus requirement decreased with age. Using inorganic phosphorus…

FOLLOWING our observations (Berg, 1963) that certain commercial phosphorus supplements contained sufficient vanadium to suppress growth of chicks when added to a corn-soy ration, a preliminary study was made to compare the performance of laying hens fed rations supplemented with “high vanadium” and “low vanadium” phosphate sources. The results of the preliminary test suggested that a more detailed study of the effects of adding varying levels of vanadium to a laying ration should be made. PROCEDURE In the preliminary study, 40, approximately 12 months old, strain cross White Leghorn hens were divided into four groups of 10 each. The birds were kept in individual wire cages. Two diets, differing only as to source of tricalcium phosphate, were prepared using the formula of ration 1, Table 1. Each diet was fed to two groups for eight weeks. Haugh units and shell thickness were determined for three eggs laid by each bird…